Load indicator for transformers



Patented Aug. 10, 1926.

assegni earner eric.

I-IARRS D. I-IINELINE, 0F AKRON, OHIO, ASSIG-NOR TO XVESTINGHOUSE ELECTRIC it MANUFACTURING COMPANY, A CORORATON O 'ENNSYLVANl-L LOAD INDICATOR FOR TRANSEORMERS.

Application led. November 14, 1922. Serial No. 600,9l1.

My invention relates to electric transormers and more particularly to means tor indicating the temperature within such transformers.

One object of my invention is to provide a signal device which will indicate the temperature within a transformer casing, in combination with means for Calibrating the temperature at which the signal is actuated.

Another object of my invention is to provide a thermal indicator comprising a bimetallic element and a signal device released upon a predetermined distortion of said bimetallic element, and means for calibrating the temperature at which the bimetallic element releases the signal.

A further object ot' my invention is to provide a spring bearing' on a bimetallic element with adjustable means v'for varying the forces exerted by the spring on the bimetallic element.

It is also an object oi my invention to provide a thermal indicator with means for automatically compensating the indicator in accordance with changes in the ambient temperature after the device has been tested in service.

In the application of William M. Brad,

shaw iiled December 7, 1920, SerialNo. 129931, and assigned to the lVestinghouse Electric Si Manufacturing Company, is shown and described a temperature indicator for transformers ci this general character. My invention provides an improvement in the calibration ot such indicator with relation to the desired temperature within the transformer casing.

In the accompanying drawing,

Figure l is atace view of an indicator embodying my invention and occupying its closed position.

Fig. 2 is a similar view of the indicator in an open or operative position.

Fig. 3 is a transverse sectional view of the indicator.

Fig. 4C is a longitudinal sectional view of the temperature indicator.

Fig. 5 is a fragmentary view, in perspective, of the indicator and thermoresponsive member in the non-indicating or latched position.

In the several figures of the dra-wing, similar reference numerals indicate like parts.

In the preferred embodiment of my invention, a cover l encloses a substantially rectangular trame 2. The trame 2 is secured by rivets 3, or bv welding, to a cylinder 4L that is inserted in a threaded bushing 5 and that houses a bimetallic thermally responsive member 6. rlhe inner end of member 6 is rigidly secured within the cylinder 4;. as is shown in Fig. 4.

fr target or semaphore 7 is mounted in the iframe l and is normally detachably held in engagement with the bimetallic member 6 by a suitable latch 8 rigidly mounted on the back ci the vsemaphore 7. A spring 9 is suitably secured, at one end l1, to the iframe 2, as by crimping, welding or soldering. The free end or spring 9 bears against bimetallic member 6 and normally biases that member ,into a position where it engages the latch 8. A bimetallic member l0 is secured, at one end, to the end 1l ot the spring` 95 and, at its free end, bears lirmly against the spring 9 adjacent to the point of contact between the 'spring 9 and the bimetallic member 6, as is shown in Figure 3. rlhe bimetallic member 10 is designed to normally bend` upon an increase in temperature7 in a direction opposite to that ot the member 6.

Mounted on the casing 2 is a cam 12 which ears against the spring 9. A scale 13 and a pointer let serve to calibrate the pressure exerted by the cam upon the spring.

lin the operation of my inventionE the temperature applied v.to the cylinder a results ina corresponding distortion ot the bimetallic member 6, in a manner characteristic o'l' bimetallic strips. After a predetermined movement of the tree end of member 6, it moves from under the latch S, thereby allowing the latch 8 and the attached semaphore 7 to tall by `mavity. rIhis action may be understood by reference to Fig. 3 of the drawing, wherein movement of member 6 to the left, against the pressure of spring 9. permits the semaphore 7 to fall. The construction of cylinder 4L, bushing 5 and bimetallic member 6 is such that the frame 2 normally assumes a vertical position. These features, however, do not constiute the subject-matter of my invention.

The spring 9 is positioned to normally oppose the movement of the bimetallic member 6 during increase of the temperature surrounding it. The cam member l2 is so mounted on the trame 2 that it forms a fulcrum about which the :tree end of the spring 9 turns, against the force of the bimetallic membeis 6 and l0. By varying the distance between the aXis of the cam l2 and the point of tangency to the spring 9, an accompanying variation in the pressure applied to the member G is produced. By Calibrating this movement with relation to a lined scale 13 for various desired temperatures Within the device to be protected, it is obvious that the signal 7 may be set to operate at any predetermined tempera ture. During the slight thermal changes which take place because of changes in the ambient temperature Within the indicator traine, the bimetallic members 6 andlO tend to move in opposite directions, the bending of the member l0 results in a decreasing force exerted on the spring 9, permitting the latter to exert a correspondingly increasing force against the bimetallic member 6.

Bimetallic member l0 is tar enough removed 'from the temperature of the oil in the transformer tank that it is not appreciably al'lected thereby, but remains an automatic compensating means for changes in the ambient temperature ot the air surrounding the indicator.

By my invention, it is possible to calibrate the sa'le Working temperature of the electrical device for changes in seasonal temperatures, as Well as the current-carrying capacity ot the electrical device.

iVhilel have shown and described a preferred form ot my invention, it is to be understood that such changes may be made in the torni and arrangement ot the coin-- ponent parts thereof as fall Within the spirit and scope of my invention as delined in the accompanying claims.

l claim as my invention:

l. ln a thermal indicator, a thermo-responsive element, means for biasing said thermo-responsive member into a predetermined position, a semaphore detachably secured by said thermo-responsive member When in the predetermined position, and cam means t'or controlling said biasing means.

2. In a thermal indicator, a thermo-responsive element, means for biasing said hernie-responsive member into a predetermined position, a semaphore detacliably sccured by said thermo-responsive member when in the predetermined position, and a cam in combination Withv an indicating scale for controlling said biasing means.

ln a thermal indicator the combination with a thermo-responsive member, an indicator, and means for releasing said indicator upon predetermined excitation of said thermo-responsive member, of a resilient member biasing said thermo-responsive element into a normal position, and a cam for controlling the degree of bias in said resilient member.

dl. temperature indicator for a heat-developing translating device, comprising a movable semaphore having indicating and non-indicating positions, a thermally-responsive member subjected to the temperature of a portion of the translating device for releasably supporting said semaphore and a second thermally-responsive member subjected to the temperature of the ambient air i'ior compensating said first named thermally-responsive member.

5. rlhe combination with a thermo-responsive element, et means comprising a manually adjustable thermostatic member for initially biasing said thermo-responsive element into a predetermined position to vary its operative temperature.

6. The combination With a bimetallic member, o' means comprising a manually adjustable and oppositely acting bimetallic member for initially biasing said i'rst bimetallic member into a predetermined position for varying its effective temperature.

7. rlhe combination With a thermo-responsive element, of a resilient member Jr'or biasing said thermo-responsive element into a predetermined position, a second thermoresponsive element associated With aid lirst element and said resilient member,

and manual means for initially adjusting the orce oiC said resilient member and said second thermo-responsive element.r

ln testimony Wliereo'l, I have hereunto subscribed my name this 3rd day ot November 1922.

HARRS D. HINELINE.

Certicate of Correction.

It is hereby certified that in Letters Patent No. 1,595,781, granted August l0, 19,26, upon the application of Harris D. Hineline, of Akron, Ohio, Jfor an improvement in Load Indicators for Transformers;7 'an error appears in the printed specification requiring correction as follows: Page 2, line 88, claim 6, after the Word effective insert the Word 0j9enatz'ng,i and that the said Letters Patent should be read With this correction therein that the same may conform to the record of the case in the Patent Ofice.

Signed and sealed this 28th day of September, A. D. 1926.

[SEAL] M. J. MOORE,

Acting Clonv/ni/z'ssvz'oneia of Patents. 

